Comments by "Engineering the weird guy" (@engineeringtheweirdguy2103) on "Donut" channel.

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  2. If we're talking about grid to vehicle efficiency, (which im assuming you mean includes transmission losses and power plant losses), then much of that is redundant when comparing green hydrogen to BEV's. As they both require electricity from the same source. However hydrogen requires 3-4 times the same amount of energy per miles from the same grid as BEV. Charging of a BEV is between 85-98% efficient depending on how you do it. Batteries themselves are highly efficient. Hydrogen, is not so much. Fuel cells are around 60% efficient and hydrogen combustion is only around 20-25% efficient. That means that home and small scale hydrogen production would not be very favourable over putting that solar or grid energy into a BEV. If you're getting hydrogen from water you need much more of that same energy per mile. For example the Mirai gets 400 miles on 5.6kg of hydrogen. If you put 3kWh from a solar cell into producing hydrogen, assuming even high efficiency electrolysis you'll get 2.25 kWh worth of hydrogen (Just less than 0.07kg of hydrogen) that will be able to transport you 5 miles. Put that same energy into a Tesla Model 3 with a range of 325 miles on a 75 kWh battery pack, and assuming home charging efficiencies of 98% (which we will reduce to 90% for demonstration purposes) that will get the model 3, 13 miles of driving. The other thing is that whilst hydrogen is light weight it takes up alot of space. EV batteries used in Teslas have a Volumetric Energy Density of 0.71 kWh/L. (not to be confused with hydrogens superior Gravimetric energy density in kWh/kg). Hydrogen as a gas does have a Volumetric energy density of 1.4 kWh/L, however thats not the full story, fuel tanks are round on all sides and tubular with a 3:1 length to diameter ratio, necessary to reduce stress concentrations in corners. When ever you put a round shape into a rectangular body like in a car, you get wasted space (draw a circle inside a square and note the wasted space in the corners). Further to that the fuel tanks have 1 inch thick walls adding 2inch to the diameter. With all that space not used for storing hydrogen gas, you get 0.62 kWh/L. But not all of that fuel is going to be used, for a fuel cell (being the most efficient use of hydrogen) you only use 60% of that fuel, meaning you have 0.37 kWh/L practical volumetric energy density, (about half that of batteries). Then if you consider that Hydrogen now also needs its own battery pack for adequate acceleration as well as an engine sized fuel cell, you have an overall practical volumetric energy density of almost 0.003kWh/L inclusive of the volume taken up by the battery and the fuel cell (which would obviously change depending on the battery and fuel cell size, but the fuel tanks will remain around 0.37kWh/L). To fit 400 miles worth into a car is challenge. And you can see the results in the Miari with its boot being so small that its nearly 100L smaller than that of a Toyota Yaris half it size, and the cabin space being so small you cent even fold the rear seats down extend the boot. All that sacrifice in practicality in terms of space, speed and cost of fuel per mile for only 75 more miles of range. Ontop of that hydrogen has a very short life, Most hydrogen vehicles come off the assembly line with an expiration date limiting the life of the car to only 15 years. Whilst the fuel cell itself is only rated for 100,000 miles to 150,000 miles depending on the manufacturer with Hyundai expected to announce a 200,000 miles life fuel cell late 2022. For those reasons I dont see hydrogen as being a good option.
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  11.  @touyube481  couple of corrections. In terms of long range vehicles and freight, unfortunately BEV's also have the advantage there with better ranges, power and cost charactorists. Hydrogen simply takes up too much volume. So whilst weight isnt an issue, and you can theoretically stack on more fuel with little impact on consumption per mile, unfortunately in practice there is a limited volume where you can store fuel before needing to build a larger and heavier vehicle. Batteries on the other hand have less than half the volumetric requirements of hydrogen, so whilst more batteries means more weight, but also more range, You can fit far more batteries in meaning you can get far more range. For example the flagship hydrogen semi at the moment is the Hyundai Xcient, which cant even get to freeway speeds unloaded (because fuel cells are famously low power output) but also has a 400 mile range despite having double the fuel tank volume of a standard semi. Meanwhile the Tesla semi can get 100 miles more at 500 miles whilst being faster than a tradition truck and allowing more cabin space and shorter wheel frame. The other thing I want to correct is the fuel cell degradation. The fuel cells dont degrade in the same way. But I would argue worse. Firstly they're only rated for a mere 100,000-150,000 miles. Which excessively small, especially compared to BEV batter lives. The fuel cells are degraded by air contaminants. although they are filtered, filters are never 100% effective and it does affect the fuel cell. Especially during start ups after production pauses. What happens then is you end up putting more fuel through for less power. You vehicle becomes slower and weaker and less fuel efficient. Where as before the 5.6kg in a Mirai got you 400 miles. By end of life that same 5.6kg would only get you 200 miles. And when you started with a fairly dismal acceleration of 9.2s 0-60mph. That would blow out to 12-13s -60mph. This means you're paying just as much for less. By comparison when a battery degrades, its ability to be charged is compromised. Where as before you would charge 75kWh, now you can charge 60kWh at its end of life. You're only using 60kWh to charge the battery. So you're not paying for 75kWh of electricity, only for the 60 that the battery can hold. It doesn't degrade the efficiency of the motor or the vehicle meaning your electricity consumption per mile is the same and thus, your cost per mile remains the same and so does your performance. So instead of paying $80-$90 for 400 miles at the start, and by the end, paying $80-$90 for 200 miles and much less performance. For a battery, only the range is affected.
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  31.  @Phill0old  it’s also easier to store a lot of gasses than it is to store electricity, however hydrogen isn’t one of them. Hydrogen atoms are so small they can leak through solid steel so already not an easy thing to contain, then you have to realise it has to be stored in a vessel not made of steel which has to withstand 700+ bar. Which is 32 times the pressure of LPG. Then you also have to make this not steel super strength containment vessel anti-puncture because hydrogen is extremely volatile and will readily explode with minute amounts of air. It’s more explosive than LPG, petrol fumes or even some explosives. Then you have to get this non steel, super strong, anti puncture tank and cool it. Because hydrogen has a very low inversion temperature, meaning that while most gasses, as they are taken out of a containment vessel, cool down substantially, hydrogen heats up substantially. So as you draw the gas out it gets hotter, as it gets hotter the liquid vapour pressure increases and it starts to boil off, as it does that it has to be safely discharged from the tank to avoid an explosion. So you need a non steel, super strength, anti puncture cryogenic storage. So not so much easier than putting electricity in a battery huh? But I guess that’s all not something that the media mentions with hydrogen. It would be bad for hydrogen if people found out that your fuel leaks out of your fuel tank as you drive, while it’s releasing boiled fuel because the tank is depressurising, and it means hydrogen fuel tanks only last around 3 years. Infact. I’m not sure about modern hydrogen but the first hydrogen car produced by Toyota would have to release 1/3rd of its fuel into the air through release valves due to the liquid hydrogen boiling off.
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  34.  @stefanmetzeler  I wouldnt be so arrogant. i'll go down paragraph by paragraph but I'm not touching the Climate stuff as that is outside my area of expertise. I'll stick to EV stuff. Batteries represent a substantial combustion risk? no they don't. Firstly most battery fires are thermal runaway, which takes hours of smouldering before visible flames. secondly, in relation to EV's. real-world statistics don't support your anecdotes. according to the Beuro of Statistics both In the EU, Australia and the US, the AANCAP safety board, NCAP safety board and NHTSA EV's are typically 11 times less likely to spontaneously combust, and 5 times less likely to combust in an accident. Id love to see you support your claim that EV's pose a raised likelihood of combustion. next, you claim there is alot of loss in energy transportation? no there isnt. The most ineffective powerlines in the US only represent a 15% loss of energy at worst and typically sits much lower. and by loading process i believe you mean charging? EV batteries charge at about a 98% efficiency. so thats false also. Next, Batteries do lose charge over time. But not much. My EV was parked in long term airport parking for a month and I lost less than 4% charge. But tell me, how often do you leave your car, which you can charge at home, and leave connected to the charger, sit around for months without a power supply? If you own a car, chances are its because you have use for one. The next one. and this is a BIG one. Im especially interested to see you back this up. You claim EV batteries today dont last longer than 7 years. Where in the flying huntsman did you get that from? Modern EV batteries have a Warranty Period of 8 years alone! meaning they'll last much longer than that. They need to otherwise the company will start losing money hand over foot on warranty claims. Modern EV batteries have been showing that they'll last, and have been lasting over 400,000-500,000 miles (800,000 km). That represents approximately 30-40 years of driving for the average person and much longer than the lifespan of a combustion engine. For example, Tesla Batteries have a cycle life of 1,500 cycles to 70% health. As in, after 1,500 cycles you have 70% of your original capacity remaining. For a model 3, its range is 325 miles (with the model S and X having lager ranges as well as other EV models). after 1,500 cycles that's 487,500 miles of driving. and you still have 230 miles of range to a charge at that point. and when the average daily commute is 70 miles. That seems more than still usable. So please, Id love to see you support that claim. Next is range. Most EV's are shooting at around the 400km mark these days as entry levels. For example the 2021 Nissan leaf gets 385km of range. The Tesla Model 3 Standard Range gets a realworld range of 400km. So you wont have to stop every 200km, thats half your range. Additionally super chargers are everywhere, if you're on a long trip, a stop at one of these bad boys can charge you up fully in 45 minutes with a V2 charger or 20 minutes with a V3 charger and less time if you dont need a full charge (lets say you get to the charger at 30% charge instead of 1%). Every other instance you are charging from home, While you're not using it, while youre sleep or doing something else like cooking dinner. In that instance, you dont wait at all for a charge. you just take up the next day to a full tank of gas. You dont have to drive to a fuel station every week for gas which wastes the average person between 16-17 hours per year. so spending an additional 1.5 hours of a 1,600 km road trip i might do once per year is a lot better than wasting 16-17 hours per year standing outside holding a pump dont you think? Then there is grid loading. Whilst you're absolutely correct that you cant tell people to just charge their cars at night, how many people do you know who have jobs in which they cant do that, and what percentage of the population do you think they represent? a small proportion statically would be the correct answer. The vast majority of people don't need to travel more than around 100km per day (on the extreme end). for their daily commutes, shopping etc. The vast majority of people dont use their vehilces whilst they are sleeping. Hence they charge them at night when they sleep. The load on the grid is minimal at night, many generators are shut down because there simply isnt the demand. Additionally this is a stupid point ignorant people make because its supposing that everyone receives their brand new tesla tomorrow and their gas cars are taken away. every person on the planet. Wow. what a coincidence and logistical miracle the would be! No, the world doesnt work like that. EV's have been successful on the market for over a decade now. They still make up a small (but growing) portion of the vehicle market. It will be decades still before all new vehicles are electric, and decades still before all second hand cars are electric. Meanwhile Grid capacity in every developed country has failed to, on average, double its energy capacity every 20 years due to continually rising demand ever since the light bulb was invented. meaning that the grid is more than capable of keeping up with EV adoption, as it occurs. We're not all going to get one at once. you can calm down. Next, you dont have to replace existing energy infrastructure for EV's. Even on coal only grids they produce less emissions than combustion cars do, even before you start considering transport of fuel and fuel refining. Secondly Nuclear is not the way forward. Nuclear in all industrial instances, produces radioactive waste, it also produces irradiated contaminated waste. At current we have no other option but to bury that waste in the ground and pray it doesnt eventually leak through the corroding steel drums. There is so treatment out there right now for nuclear power plant waste. Additionally, currently, unless you're china you cannot but a nuclear reactor in less than 8 years from project commission. By the time they're built, it will already be too late. conventional green energies such as wind and solar, hydro and geothermal can be very stable and reliable. When coupled with source and geographic diversification and storage. There have been many papers researching this and they all come to the same conclusion. Even look at the state of South Australia. They have over 70% renewables. with big battery storage. Before they invested in renewables, they were the least stable grid in the state, they were energy dependant on other states and had the most expensive electricity prices in Australia. Now they have the second cheapest wholesale energy prices in Australia, are net exporters of electricity to other states and have the most stable grid in Australia reaching 70% renewables. how did they do this? they diversified the type of renewables they used and the diversified, their location (part of this was rooftop solar through home solar incentives to for a VPG or Virtual Power Plant). If the wind dies down in one place, 1,000 km away its likely still windy. They also implemented storage which significantly reduced the curtailment of renewables. They did this both with grid scale battery storage, and with home storage. They are also in talks to connect their grid to Tasmania who runs entirely on Hydro, to used pumped hydro storage to further increase their storage capacity. This isnt an uncommon or unknown thing. The EU is looking at something called the EU super grid. Which will connect Solar from countries like Portugal, wind from places like Germany and Belgium with hydro storage in places like Norway. MANY studies have been done on renewables grid stability. They almost always come to the same conclusion. On their own, they're unreliable and ineffective, Diversified by source and geography, and with storage to reduce curtailment, they are reliable and effective.
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  45. How the hell did you work that out? Firstly 1L/min of hydrogen is not 1kg/min of hydrogen. Hydrogen does not have the volumetric density of water. In 6kg of hydrogen compressed to 700 bar, it equates to around 160L. If it was flowing at 1L/min it would take 2 and a half hour to fill. Also you cannot create 6kg from a home solar array. Because it takes ALOT of energy. Let me give you a real world example. Toyota recently announced they had finished installing a Hydrogen station/production plant in one of their old factories in Melbourne Australia. Its a 200kW system. (you get 3kW from your wall outlet in Australia and just under 2kW from wall outlets in the US). with this massive 200kW electrolyser, it creates 80kg of Hydrogen in 24 hours. Meaning you will use 4,800 kWh to produce 80 kg of hydrogen (not including power needed for compression). Thats 60kWh of electricity per kg of hydrogen. That also means with a whole 200kW, (more than you'd ever get to your home, solar or not) it takes 3.3 hours to make 1kg of hydrogen. Now lets say you have an average sized roof. You would only be able to fit approximately around 7kW of solar on your roof. This would become around 5kW once it passes through the inverter. during a sunny summers day in Australia, you'd produce around 42 kWh. That would be enough energy produce, 0.7kg of hydrogen or around 1/10th of a full tank per day. Put that on a trailer you'd be lucky to get more than 2kW of solar, meaning you'd only make 17 kWh of solar making 0.3kg of hydrogen. That 0.7kg of hydrogen you can make at home per day, (excluding the power required for compressing it). you'd be able to travel 50 miles in a hydrogen car. Put that same 42kWh into a Battery Electric car of the same size and you can drive 200 miles. Take the 17 kWh from the trailer solar, for a Hydrogen car that wold get you 21 miles, Put that into a Battery electric car of the same size and it will get you 81 miles.
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  48.  @AdrenalineandEpiphany  Also for the trailer example you have me, That massive solar sail ontop was a 2kW system with 1kW of wind totally 3kW potential which we've already discussed how much hydrogen is created by a 3kW system. But during the demonstration there was no wind so it would only be able to peak at 2kW. Also worth noting that you wont get 3kW all throughout the day. If it was windy enough you might get 3kW for an hour or two at noon, but it would wane in the morning and evening. He also noted that you store the hydrogen in propane tanks. This mean you wouldnt be able to use them for your hydrogen car. Why? because propane tanks have a maximum pressure rating of 20 bar, 32 times less than the 700 bar required to fill a hydrogen car. A hydrogen car tank empties at 10 bar, meaning there is no longer enough pressure to push the hydrogen through the fuel cell. You would even be able to put half of the hydrogen you make into a completely empty hydrogen car and nothing into a hydrogen even on a fuel warning light. Propane tanks typically store gas at 13 bar but max out as a physical pressure limit at 20 bar. There is also another problem with using propane tanks. Hydrogen in its gaseous state can leak through solid metal. you'd lose as much as 30% of your hydrogen in one month. But when it does do this, it embrittles the steel as it does so. compromising the strength and integrity of the propane tank. meaning that a Propane tank used to store hydrogen would need to be replaced every year or so otherwise you risk explosion as the metal becomes too brittle to store the hydrogen. All round its impractical, and wont work.
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